TUNIS, Tunisia (AP) — Tunisia’s prime minister on Tuesday branded an ultraconservative Islamist group implicated in last year’s U.S. Embassy attack as a terrorist organization with links to al-Qaida.

Ali Larayedh said in a press conference that the Salafi group Ansar al-Shariah was considered a terrorist organization based on seized documents, confessions and weapons captured. The designation means that membership in the group is now a crime.

“There will be no respite in the struggle against terrorists and against those who take up arms against the citizens and institutions of the state,” he said. “We will ensure Tunisians have a future characterized by freedom and well-being.”

The group is believed to have helped to orchestrate an attack in September on the U.S. Embassy by protesters angered by a U.S. film mocking Islam; four assailants were killed in the clashes.

The government, led by the moderate Islamist Ennahda Party, has also said members of the group were involved in the assassination of two opposition politicians this year and are cooperating with armed militants fighting the army along the Algerian border.

Larayedh urged members of the group to quit or face prosecution.

As the birthplace of the Arab Spring revolutions and home to a relatively educated population, Tunisia’s transition to democracy is being closely watched. The process has stalled following the latest political assassination in July and nearly a third of the members of the elected assembly have withdrawn, calling for a new technocratic government.

Larayedh said the current government would first finish the constitution and the electoral law by October before handing over the running of the election by the end of the year to a new government.

The opposition has rejected this proposal and is holding anti-government demonstrations this week.

“It is time for Ennahda to realize that the change of government is not a choice but a necessity,” said opposition leader Nejib Chebbi of the center-right Al-Jomhouri party.